Abstract
Purpose :
To quantitatively evaluate the efficiency of modern multi-purpose solutions (MPS) ( BioTrue (BT), PureMoist (PM) and Revitalens (RL)) in removing tear proteins from pHEMA-based model soft contact lens material and tear lipids from model silicone-hydrogel (SiH) surface in vitro.
Methods :
Quartz crystal microbalance with dissipation (QCM-D) method was used to quantify the mass of model tear proteins and human tear lipids extracted (HTLe) from worn AirOptix lenses. The model surfaces studied were 25-35 nM films of pHEMA+5% pMAA spin-coated on Gold QCM-D sensors. Silicon sensors were silanized by octyltrichlorosilane (OTS) to mimic SiH lens surface. Egg white lysozyme (Lys,1 mg/ml in model tear electrolyte solution (MTE)), milk β-lactoglobulin (Lg, 1 mg/ml in MTE), and Bovine mucin (Bm,0.03 mg/ml in MTE) were used as mixed (Lys:Lg:Bm = 2:1:0.3;1 mg/ml total) solutions. The proteins were adsorbed on pHEMA+5% pMAA for 16-20 hours at 35.5°C, rinsed with MTE, and exposed to MPS for 16-20 hours at 22.5° C. HTLe solutions of 1-1.5 µl were spread on OTS-Si sensors, exposed to MPS flow for 16-20 hours at 22.5° C, then washed with MTE. Sauerbrey model was used to calculate the masses.
Results :
The residual amounts of PM and RL were 25±5% and 18±3% of total adsorbed PM and RL,respectively, on pHEMA+5% pMAA without proteins; however, BT was totally removed from model pHEMA materials. Treatments of model tear proteins adsorbed on pHEMA materials with RL and PM increased total mass by 0.4±0.05 µg/cm2 and 0.55±0.06 µg/cm2, respectively; whereas BT significantly reduced proteins mass by 0.2±0.05µg/cm2 (p=0.016) (i.e., 45±5% of total proteins was removed). Exposure of HTLe deposited on model SiH surface to BT and RL increased total mass by 36-40%, whereas PM significantly reduced the mass of lipids by 25±5% (p=0.034).
Conclusions :
All proteins and their mixtures bound irreversibly to model pHEMA surfaces. Some components of PM and RL bound irreversibly to model pHEMA materials. Our results suggest that BT is more efficient in model tear-protein removal from model pHEMA materials than RL or PM. The latter tend to accumulate into pHEMA materials and cannot be removed by prolonged washout. Treatment of HTLe with PM partially removed lipid deposits from a model SiH surface. These findings may provide some guidance for proper choice of lens material-MPS combination.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.